Dislocations penetrating an Al/Si interface

We study indentation of a nanolayered material consisting of a Si top layer above an Al substrate, using molecular dynamics simulation. We focus on the activity of Si dislocations upon reaching the interface. We find that passage of the dislocations through the interface is possible, if the slip systems of the two crystals are aligned. Upon absorption at the interface, the Si dislocations generate slip which leads to 1-monolayer deep interface pits with well-defined steps; on the Al side dislocations and stacking fault planes are generated, which are pinned to the interface pit. For interfaces with not well aligned slip systems, the passage of dislocations is strongly suppressed. However, still interface pits, albeit with less well defined contours, and stacking fault planes aligned with the interface are created